VMware vSphere® High Availability (HA) monitors all virtualized servers and detects physical server and operating system failures. VMware High Availability can improve the availability of VSP One File and make file deployments more robust.
vSphere Fault Tolerance (FT) provides continuous availability for applications if a server fails.
The following are the HA and FT configuration options:
- VMware vSphere vMotion® and Storage vMotion®: Provide manual and automatic migration of compute and storage without service interruption. The three vMotion scenarios are:
- Host-only migration (with shared storage) moves VM execution from one host to another.
- Storage-only migration (single host access to two storage pools) moves a VM disk image from one storage pool to another storage pool.
- Host and storage migration combines both host and storage migration.
The risk of losing quorum is none to minimal. However, vMotion does not protect against an ESXi host loss.
- Cold standby: In an ESXi HA cluster, if the ESXi host running VSP One File fails, a new instance of VSP One File starts on another ESXi host. The new instance uses the last updated disk image from the shared storage. Although recovery is fast, it requires starting the VM, which is not fast enough to prevent a quorum loss. If the VSP One File cluster is healthy, a HA failover does not affect its availability, but it does prevent access to the management software and the CLI while the new instance of starts.
The risk of losing quorum is high to certain.
- Hot standby: With FT on, a the secondary VSP One File instance (on a different ESXi host) takes over immediately from a primary VSP One File if the primary fails. This requires a 10-Gbps FT logging network in addition to the normal network that connects the ESXi hosts and the VSP One File nodes. If VSP One File serves as a quorum device, the failover should be within the 5 second requirement before a quorum loss occurs. In this case, a HA failover can occur without affecting the File cluster, even if one of the file nodes is down.
The risk of losing quorum is none to minimal.
In summary, HA provides a highly available VSP One File, but failovers can cause a short-term loss of quorum. FT provides a highly available VSP One File with a negligible chance of losing quorum.